Redbird,
Alvin is right on the money!
According to this resource on the
1954 Chevrolet Trucks, an "automatic" transmission was first listed as optional equipment for Chevy light trucks..
I checked '53 and earlier Chevrolet documents and there was no mention of an optional automatic transmission.
On a related note, this resource document on
1953 GMC Truck Hydramatic Transmissions indicates GMC offered it 1 year earlier in their 1953 light duty trucks.
This is after some variations had already been used in various WWII military vehicles and the M135 series 2.5 ton trucks starting in 1950 (info in above document).
Lots more articles and info can be found through web searches on "Hydramatic" transmissions.
Dan
